How greedy/stupid do you have to be to short a bankrupt biotech that's winding down operations? I work in biotech and wouldn't touch penny stocks in the sector, long or short. And as for the reason KBIO exploded, that guy Shkreli (of Turing) bought up most of the shares, supposedly because lenzilumab, KaleBios' lead product which just failed a P2, demonstrated efficacy on its target (GM-CSF), and so he wants to advance lenzilumab into a P1 in CMML. Knowing how tough it would be to take Turing public though in this environment, I wonder if the real reason is he'll just use KBIO's shell to go public via a reverse merger, and lenzilumab is an added bonus he gets for pennies.